As methods of manufacturing electronic components, methods comprising a bonding step of bonding an electronic component assembly having a plurality of circuit patterns formed on a wafer or insulating substrate to an adhesive sheet, a cutting/separating (dicing) step of cutting the bonded wafer and electronic component assembly into separate chips, a UV irradiation step of irradiating with UV rays from the adhesive sheet side to reduce the adhesive force of the adhesive layer, a pickup step of picking up the diced chips from the adhesive sheet, and a mounting step of applying glue to the bottom surfaces of the picked up chips and mounting the chips on lead frames or the like by means of the glue are known.
Regarding the cutting step, a method of bonding the wafer or electronic component assembly to an adhesive sheet and further securing the adhesive sheet to a ring frame before cutting and separating (dicing) into separate chips is known.
A method using an adhesive sheet (die attachment film-integrated sheet) having both the function of an adhesive sheet for dicing and a glue for mounting the chip on a lead frame or the like, formed by layering a die attachment film on the adhesive sheet used in a manufacturing method as described above has been proposed (Patent Document 1, Patent Document 2). By using a die attachment film-integrated sheet to manufacture electronic components, the step of applying glue after dicing can be omitted. Die attachment film-integrated sheets excel in thickness control of the glue portion and suppression of excess glue as compared with methods using a glue to bond the chip to a lead frame. Die attachment film-integrated sheets are used in the manufacture of electronic components such as chip size packages, stacked packages and system-in-packages.
There are manufacturing methods in which the step of applying glue after dicing can be omitted by applying a paste-type glue to the semiconductor wafer, then semi-curing in the form of a sheet by heating or UV irradiation, to form a semi-cured glue layer.
However, the trend toward higher integration of semiconductor components has caused chips to become larger and thinner, thereby increasing cases in which difficulty is encountered in chip pickup after dicing. Furthermore, since dicing involves dicing not only of the semiconductor wafer, but also of the semi-cured glue layer and adhesive layer of the adhesive sheet, the semi-cured glue layer and the adhesive layer can become intermixed on the dicing line, so that even if the adhesive force is reduced by irradiation with UV rays after dicing, the ease of separation during pickup can be poor, sometimes resulting in pickup failures.    Patent Document 1: JP 2006-049509 A    Patent Document 2: JP 2007-246633 A